A document released by the Ministry for Primary Industries urged farmers to make an informed decision on the use of local or imported semen.
While imported semen was tested for the disease “the tests are not particularly reliable”, it said.
The information noted that while semen was considered a low risk in the spread of Mycoplasma bovis, it was a possible entry pathway for the cattle disease found here in July.
MPI had not yet determined how the disease entered New Zealand.
Mycoplasma bovis was present in most other countries in the world, including countries that NZ imported semen from.
The Import Health Standard that regulated the import of semen recognised it was a potential pathway.
“Antibiotics routinely used in the processing of frozen semen may not be completely effective in killing mycoplasmas and Mycoplasma bovis can survive freezing,” MPI said.
MPI recommended farmers ask their semen supplier what assurance they could give that insemination would not lead to an outbreak of Mycoplasma bovis in their herd.
Farmers should also question whether the donor bulls had been tested for the disease and what assurance the company could give that their semen was free of Mycoplasma bovis.
The main way the cattle disease spread from farm to farm was by the movement of infected animals so farmers managing service bulls should also check the source herd and understand its health history before buying or leasing bulls.
Once bulls arrived onfarm they should be kept separate for a few days so their health status could be monitored.
If leasing bulls out for mating it was recommended that bulls were quarantined on their return for seven days and thoroughly checked for lameness and any signs of respiratory disease.
More information was available through MPI, the NZ Veterinary Association, DairyNZ and Beef + Lamb NZ.
